Supramolecular chirality of amphiphilic block copolymer films made through two steps: self-assembling first, and then solution coating.
Supramolecular chirality of amphiphilic block copolymer films made through two steps: self-assembling first, and then solution coating.
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DOI：
10.1039/c7sm01635b
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发表时间：
2017-11
期刊：
影响因子：
3.4
通讯作者：
Yingjue Wang;ZhenZhen Zhang;Yanggang Gao;Gang Zou;Qi-jin Zhang
中科院分区：
文献类型：
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作者：
Yingjue Wang;ZhenZhen Zhang;Yanggang Gao;Gang Zou;Qi-jin Zhang
两亲嵌段共聚物薄膜通过先自组装再溶液涂覆两步制备，获得了超分子手性。该两亲嵌段共聚物由聚n -异丙基丙烯酰胺（pNIPAM）为亲水段和聚甲基丙烯酸甲酯（手性侧基）为疏水段组成。两步制备的薄膜在200 nm波长附近显示出明显的圆二色性信号。然而，直接在石英表面涂覆共聚物溶液制成的薄膜不能检测到CD信号。约200nm处的CD信号来自于疏水段中与手性基团相连的苯单元的超分子排列。这一结果被认为是由于共聚物在成膜过程的第一步聚集，并对影响这一过程的因素进行了相应的研究。两步制备的膜对手性小分子具有对映选择性吸附能力，而直接包覆共聚物溶液制备的膜则没有这种对映选择性吸附能力。
Supramolecular chirality is achieved in amphiphilic block copolymer films made through two-step fabrication: self-assembling first and then solution coating. The amphiphilic block copolymer is composed of poly(N-isopropyl acrylamide) (pNIPAM) as hydrophilic segments and poly(methyl methacrylate) with chiral side groups as hydrophobic segments. The films fabricated by two steps show sensible circular dichroism (CD) signals around a wavelength of 200 nm. However, CD signals cannot be detected from films made by directly coating the solution of copolymers on the quartz surface. The CD signal at about 200 nm is from supramolecular arrangement of benzene units connected to the chiral group in the hydrophobic segment. This result is thought to be originated from the aggregation of the copolymer during the first step of the film forming process, and the corresponding investigation into factors affecting this process has been performed in this work. It is also found that the films fabricated by two steps can adsorb chiral small molecules enantioselectively, while the films obtained by coating the solution of copolymers directly have no such enatioselective adsorption ability.